In general, various breakers such as a main breaker, a branch breaker, and a short-circuit breaker break off the power of industrial and home electric cabinet panels and switch boards. However, it is very difficult to manufacture cabinet panels and switch boards. Also, to manufacture cabinet panels and switch boards, there is required specific equipment such as a bus bar processor.
Generally, to break off the power of cabinet panels and switch boards, a bus is connected to by using a bus bar and attached to a breaker. Also, the bus bar passes through complicated manufacturing processes such as holing, tabbing, beveling, coating, tube bending, and tube cutting. Therefore, manufacturing costs are increased and a delay in delivery is generated since it is possible to manufacture cabinet panels and switch boards only by a bus bar processor.
In general bus bars, a power source in the line of R supplies power to R1-RL-NR, a power source in the line of S supplies power to S1-SL-SR, a power source in the line of T supplies power to T1, TL, and TR, and a power source in the line of N supplies power to N1-NL-NL-RR, which allows foreign substances to be inserted into a gap generated while attaching a breaker. Therefore, there is always a danger of accidents. Also, since a location of a breaker connected to right and left of a branch breaker is out of line in a conventional bus bar connection way, which makes it impossible to fix an each phase, it is impossible to allow right and left branch breakers to correspond to each other by embodying a highly wrought connection bus bar. Also, since there is required a lot of time to manufacture a cabinet panel, it is difficult to quickly restore an emergent electric accident.
Also, when disassembling a cabinet panel or a switch board, it is difficult to recycle components since components are not standardized. Though iron covers have been used to protect an exposed charger, acryl covers are used because of easiness of manufacture. However, in this case, a toxic gas is generated from acryl on fire. Also, the charger is exposed when checking or changing a breaker, thereby generating electric shocks and short-circuits due to foreign substances.
In the case of block type power distribution apparatuses, different from general copper bus bar cabinet panel, an apparatus is divided into blocks and in such a way that power can be supplied from a main breaker to a desired branch breaker, thereby having high utility, productivity, stability, and compatibility with general breakers.
However, general block type power distribution apparatuses have problems as below.
(1) To be compatible with various breakers, it is easy to connect to each other when a height of a branch breaker terminal is identical to that of a connected branch breaker. However, there occurs a case where a certain breaker cannot be used because a height of a block type power distribution apparatus is different from that of a branch breaker. To solve this problem, it is required to manufacture an additional block type power distribution apparatus for other breakers having a different height. However, there is required another additional mold, thereby increasing manufacturing costs and reducing productivity and economical efficiency.
(2) When several identical terminals are projected while branching out a plurality of breakers from one power distribution apparatus, a breaker may be connected to a wrong terminal, thereby generating a danger such as a short-circuit, heat, and a fire.
(3) Static electricity or a short-circuit may occur since a human body directly contacts with a connection portion or foreign substances are inserted into the connection portion while a connection terminal is exposed from a bottom of a power distribution apparatus to connect to another power distribution apparatus. Also, when using identical block type power distribution apparatuses, it is impossible to show to where each of power distribution apparatuses distributes power. Accordingly, it is impossible to attach a name tag to the power distribution apparatus.
Also, a cabinet panel is an apparatus supplying external power to each branch breaker via a main breaker. Generally, copper bus bar cabinet panels are used. Plug-in type preassembled cabinet panels have been developed. In the case of a preassembled power distribution apparatus, different from conventional copper bus bar cabinet panels, blocks forming the power distribution apparatus are connected to one another to supply power from a main breaker to a desired branch breaker, which has high utility, productivity, and stability. However, the apparatus includes a main breaker terminal and a branch breaker terminal, mostly formed of a metal bar having high electric conductivity, such as copper, whose electric conductivity and stability are affected by a connection method.
Generally, to connect a preassembled power distribution apparatus, a screw thread is formed on a connection terminal and a main breaker terminal is connected by bolts and nuts, which is called as a screw coupling method. As a thickness of the screw thread, a screw contacts with the connection terminal.
However, such preassembled power distribution apparatuses have problems as below.
(1) A thickness of a screw thread is increased to increase a contact area, thereby reducing resistance, heat, and unfastening, which is considered as advantageous. However, actually, it causes increase of manufacturing costs to consume much material to increase a thickness of a terminal.
(2) A material of bus bars used in mostly cabinet panels at present is copper. Also, in preassembled power distribution apparatuses, there is a power distribution circuit formed of copper. Due to increase of the cost of copper as raw material, manufacturing costs of power distribution apparatuses are increased. Accordingly, instead of copper, which is very expensive, aluminum or economic light copper (ELC), which have electric characteristics similar to those of copper and are cheaper than the copper, are used substituted for the copper to reduce manufacturing costs.
However, it is avoided to use a material substituted for the copper due to a deformation or unfastening of screw coupling caused by heat when using the material substituted for the copper, the material which has workability or mechanical characteristics inferior to those of the copper.
(3) In the case of preassembled power distribution apparatuses, since a main breaker terminal and a branch breaker terminal are installed therein and power is supplied via the terminals, there occurs a lot of heat in a case. However, since conventional preassembled power distribution apparatuses are perfect closed, which make it difficult to discharge heat.
(4) In addition, since a main breaker terminal and a an additional breaker terminal of a preassembled power distribution apparatus have the same height, when connecting a plurality of preassembled power distribution apparatuses, a height thereof becomes gradually increased according to a thickness of a terminal.
That is, since a main breaker terminal is coupled with a top of an additional breaker terminal, a second preassembled power distribution apparatus coupled with a first preassembled power distribution apparatus is assembled as being higher by a height of an additional breaker terminal of the first preassembled power distribution apparatus. In addition, a third preassembled power distribution apparatus is assembled as being higher by an additional breaker terminal of the second preassembled power distribution apparatus. Accordingly, when coupling a plurality of preassembled power distribution apparatuses in a line, a height thereof is consecutively increased in such a way that a preassembled power distribution apparatus in a latter part gets loose from a body when fastening the preassembled power distribution apparatus to the body.